Powering devices using RF energy harvesting

ABSTRACT

Disclosed is an apparatus for an application including a core device for the application. The apparatus includes a power (preferably RF energy) harvester connected to the core device to power the core device. Also disclosed is a method for an application. The method includes the steps of converting RF energy into usable energy. There is the step of powering the core device with the usable energy.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation application ofU.S. patent application Ser. No. 12/499,618, filed Jul. 8, 2009, nowU.S. Pat. No. 8,621,245, which is a divisional application of U.S.patent application Ser. No. 11/447,412, filed Jun. 6, 2006, which claimspriority to U.S. Provisional Patent Application No. 60/688,587, filed onJun. 8, 2005; each of which is incorporated herein by reference in itsentirety.

BACKGROUND

The present invention is related to the wireless powering of devices.More specifically, the present invention is related to the wirelesspowering of devices with a power harvester.

As processor capabilities have expanded and power requirements havedecreased there has been an ongoing explosion of devices that operatecompletely independent of wires or power cords. These “untethered”devices range from cell phones, and wireless keyboards to buildingsensors and active RFID tags.

Engineers and designers of these untethered devices continue to have todeal with the limitations of portable power sources, primarily batteriesas the key design parameter. While performance of processors andportable devices have been doubling every 18-24 months driven by Moore'slaw, battery technology in terms of capacity has only been growing atmeasly 6% per year. Even with power conscious designs and the latest inbattery technology, many devices do not provide the lifetime cost andmaintenance requirements for applications that require a large number ofuntethered devices such as logistics, and building automation. Today'sdevices that need two-way communication require scheduled maintenanceevery three to 18 months to replace or recharge the device's powersource (typically a battery). One-way devices simply broadcasting theirstatus (one-way) such as automated utility meter readers have a betterbattery life, typically requiring replacement within 10 years. For bothdevice types, scheduled power-source maintenance is costly anddisruptive to the entire system that a device is intended to monitorand/or control. Unscheduled maintenance trips are even more costly anddisruptive. On a macro level, the relatively high cost associated withthe internal battery also reduces the practical, or economically viable,number of devices that can be deployed.

The ideal solution to the power problem for untethered devices is adevice or system that can collect and harness sufficient energy from theexternal environment. The harnessed energy would then either directlypower an untethered device or augment a battery or other storagecomponent. Directly powering an untethered device enables the device tobe constructed without the need for a battery. Augmenting a storagecomponent could be along two lines: 1) increasing the overall life ofthe device or 2) by providing more power to the device to increase thefunctionality of the device. The other parameters for an ideal solutionis that the harnessing device could be used in a wide range ofenvironments including harsh and sealed environments (e.g. nuclearreactors), would be inexpensive to produce, would be safe for humans,and would have a minimal effect on the basic size, weight and otherphysical characteristics of the untethered device.

SUMMARY

The present invention pertains to an apparatus for an application. Theapparatus comprises a core device preferably having an integratedcircuit for the application. The apparatus comprises a power harvester(preferably a radio frequency (RF) energy harvester) connected to thecore device to power the core device.

The present invention pertains to an apparatus for an application. Theapparatus comprises a core device preferably having an integratedcircuit for the application. The apparatus comprises means for receivingenergy wirelessly and providing power from the energy to the core deviceto power the integrated circuit of the core device. The receiving meansis connected to the core device.

The present invention pertains to a method for an application. Themethod comprises the steps of converting RF energy into usable energy.There is the step of preferably powering an integrated circuit of thecore device with the usable energy.

This invention pertains to a technique that uses radio frequency (RF)energy as a source of energy to directly power a device or augment apower storage component in a device. The present invention meets therequirements described in the previous “Background of the Invention”section.

Traditional RF receiving devices have focused on maximizing selectivityof the frequency to isolate and to be coherent without interference fromother sources. In contrast, while the present invention operates at aspecific frequency or range of frequencies, the device accepts anyinterference to supplement the output power of the device. Also, theresearch related to power harvesting that uses RF energy as a source hasprimarily focused on devices in close proximity of the source (inductiveor near-field energy). In most cases, prior research assumed a dedicatedor directed source of RF to power the device.

The invention should not be confused with power transfer by inductivecoupling, which requires the device to be relatively close to the powertransmission source. The RFID Handbook by the author Klaus Finkenzellerdefines the inductive coupling region as distance between thetransmitter and receiver of less than 0.16 times lambda where lambda isthe wavelength of the RF wave. The invention can be implemented in thenear field (sometimes referred to as inductive) region as well as thefar-field region. The far-field region is distances greater than 0.16times lambda.

It is an object of this invention to provide a method and apparatus to

-   -   1. remotely energize an untethered device without using direct        wiring    -   2. power or augment the life of the power storage component so        it matches the life of the device and, ultimately, powers the        off-grid device with or without the use of batteries    -   3. allow untethered devices to be virtually maintenance free    -   4. provide augmentation for other energy harvesting technologies        (solar, piezoelectric, etc.)    -   5. provide backup power to tethered devices

It is a further object of this invention to directly power a device oraugment a power storage component in a device in conjunction with otherpower harvesting technologies and storage elements.

With this method and apparatus a device's power storage components donot require replacement, thus enabling the device to be permanentlyplaced off-grid, where it may be physically impractical, costly, ordangerous (due to a harsh environment) to provide maintenance.

For devices on-grid (tethered) or with reliable power sources, RF powerharvesting can be used as a backup in case the primary power source islost.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings, the preferred embodiment of the inventionand preferred methods of practicing the invention are illustrated inwhich:

FIG. 1 is a block diagram of an RF Power Harvesting block used todirectly supply power to Core Device Components.

FIG. 2 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 3 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components.

FIG. 4 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 5 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components.

FIG. 6 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Components.

FIG. 7 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block.

FIG. 8 is a block diagram of an RF Power Harvesting block incommunication with a Power Storage block.

FIG. 9 is a block diagram of an RF Power Harvesting block incommunication with a Power Storage block and used to supply power toCore Device Components.

FIG. 10 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 11 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components.

FIG. 12 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andPower Storage block.

FIG. 13 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 14 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andPower Storage block and used to supply power to Core Device Components.

FIG. 15 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andPower Storage block and used to supply power to Core Device Components.

FIG. 16 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components.

FIG. 17 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andPower Storage block.

FIG. 18 is a block diagram of an RF Power Harvesting block supplyingpower to a Power Storage Charger.

FIG. 19 is a block diagram of an RF Power Harvesting block supplyingpower to a Power Storage Charger and the RF Power Harvesting block incommunication with a Power Storage block.

FIG. 20 is a block diagram of an RF Power Harvesting block supplyingpower to a Power Storage Charger and Core Device Components.

FIG. 21 is a block diagram of an RF Power Harvesting block supplyingpower to a Power Storage Charger and Core Device Components and the RFPower Harvesting block in communication with a Power Storage block.

FIG. 22 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 23 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 24 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block.

FIG. 25 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components.

FIG. 26 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 27 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block.

FIG. 28 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andthe RF Power Harvesting block supplying power to Core Device Components.

FIG. 29 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit.

FIG. 30 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andPower Storage block and used to supply power to Core Device Components.

FIG. 31 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block.

FIG. 32 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power Core Device Components.

FIG. 33 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Components.

FIG. 34 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block.

FIG. 35 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components.

FIG. 36 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Components.

FIG. 37 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Components.

FIG. 38 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to a Power Storage Charger.

FIG. 39 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to a Power Storage Charger.

FIG. 40 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to the Power StorageCharger.

FIG. 41 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components and used to supply powerto a Power Storage Charger.

FIG. 42 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to a Power Storage Charger.

FIG. 43 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to a Power Storage Charger.

FIG. 44 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andthe RF Power Harvesting block supplying power to Core Device Componentsand used to supply power to a Power Storage Charger.

FIG. 45 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to a Power Storage Charger.

FIG. 46 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Componentsand used to supply power to a Power Storage Charger.

FIG. 47 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to a Power Storage Charger.

FIG. 48 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power Core Device Components and used to supply power toa Power Storage Charger.

FIG. 49 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Componentsand used to supply power to a Power Storage Charger.

FIG. 50 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to a Power Storage Charger.

FIG. 51 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit andused to supply power to Core Device Components and used to supply powerto a Power Storage Charger.

FIG. 52 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Componentsand used to supply power to a Power Storage Charger.

FIG. 53 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation and/or Power Storage Circuit and aPower Storage block and used to supply power to Core Device Componentsand used to supply power to a Power Storage Charger.

FIG. 54 is a block diagram of an RF Power Harvesting block using AntennaA to directly supply power to Core Device Components.

FIG. 55 is a block diagram of an RF Power Harvesting block using AntennaA to supply power to a Power Regulation, Storage and/or Storage Chargingblock.

FIG. 56 is a block diagram of an RF Power Harvesting block using AntennaA to supply power to a Power Regulation, Storage and/or Storage Chargingblock and used to supply power to Core Device Components.

FIG. 57 is a block diagram of an RF Power Harvesting block used todirectly supply power to Core Device Components.

FIG. 58 is a block diagram of an RF Power Harvesting block used tosupply power to a Power Regulation, Storage and/or Storage Chargingblock.

FIG. 59 is a block diagram of an RF Power Harvesting block used tosupply power to a Power Regulation, Storage and/or Storage Chargingblock and used to supply power to Core Device Components.

FIG. 60 is a block diagram of an RF Power Harvesting block used todirectly supply power to Core Device Components.

FIG. 61 is a block diagram of an RF Power Harvesting block used todirectly supply power to Core Device Components and in communicationwith an Alternative Power Sources block.

FIG. 62 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block and used todirectly supply power to Core Device Components.

FIG. 63 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block.

FIG. 64 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation, Storage and/or Storage Chargingblock.

FIG. 65 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation, Storage and/or Storage Chargingblock.

FIG. 66 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation, Storage and/or Storage Chargingblock and an Alternative Power Sources block.

FIG. 67 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation, Storage and/or Storage Chargingblock.

FIG. 68 is a block diagram of an RF Power Harvesting block incommunication with a Power Regulation, Storage and/or Storage Chargingblock and an Alternative Power Sources block.

FIG. 69 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block and a PowerRegulation, Storage and/or Storage Charging block.

FIG. 70 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block and a PowerRegulation, Storage and/or Storage Charging block.

FIG. 71 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block.

FIG. 72 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block.

FIG. 73 is a block diagram of an RF Power Harvesting block incommunication with an Alternative Power Sources block.

FIG. 74 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components.

FIG. 75 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components.

FIG. 76 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with anAlternative Power Sources block.

FIG. 77 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components.

FIG. 78 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with anAlternative Power Sources block.

FIG. 79 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with anAlternative Power Sources block.

FIG. 80 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with anAlternative Power Sources.

FIG. 81 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with a PowerRegulation, Storage and/or Storage Charging block.

FIG. 82 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with a PowerRegulation, Storage and/or Storage Charging block.

FIG. 83 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with a PowerRegulation, Storage and/or Storage Charging block and an AlternativePower Sources block.

FIG. 84 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with a PowerRegulation, Storage and/or Storage Charging block.

FIG. 85 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with a PowerRegulation, Storage and/or Storage Charging block and an AlternativePower Sources block.

FIG. 86 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with anAlternative Power Sources block and a Power Regulation, Storage and/orStorage Charging block.

FIG. 87 is a block diagram of an RF Power Harvesting block used tosupply power to Core Device Components and in communication with anAlternative Power Sources block and a Power Regulation, Storage and/orStorage Charging block.

FIG. 88 is a block diagram of an entire power system for the device.

FIG. 89 is a block diagram of a power harvesting block used to supplypower to a core device having a sensor.

FIG. 90 is a block diagram of a power harvesting block used to supplypower to a core device having a computer peripheral.

DETAILED DESCRIPTION

A complete understanding of the invention will be obtained from thefollowing description when taken in connection with the accompanyingdrawing figures wherein like reference characters identify like partsthroughout.

There is shown an apparatus 10 for an application. The apparatus 10comprises a core device 22 preferably having an integrated circuit 36for the application. The apparatus 10 comprises a power harvester 20connected to the core device 22 to power the core device 22.

The apparatus 10 preferably includes an alternative power source 24connected to the core device 22 to power the core device 22 inconjunction with the power harvester 20. Preferably, the apparatus 10includes a power regulator 26 and/or power storage circuit 28 connectedto the power harvester 20. The apparatus 10 preferably includes a powerstorage charger 30 connected to the power harvester 20. Preferably, theapparatus 10 includes a power storage connected to the power harvester20.

Preferably, the core device 22 includes a memory 38 connected to theintegrated circuit 36 and to the power harvester 20 to power the memory36.

The core device 22 can include a sensor 32, as shown in FIG. 89. Thesensor 32 can include a proximity sensor, an intrusion sensor, anenvironmental sensor, a chemical sensor, a biological sensor, a sensorin contact with an automobile, an occupancy sensor, a motion sensor, aposition sensor, a metal detector, or a sensor 32 in contact with anaircraft. The sensor 32 can include an alarm connected to the powerharvester 20 to power the alarm, a display connected to the powerharvester 20 to power the display, a sensor 32 disposed in a building,an industrial automation sensor, a sensor 32 in contact with anelevator, a temperature sensor, a fire sensor, or an accelerometer.

The sensor 32 can include a level sensor, a gas level sensor, a fluidlevel sensor, a light level sensor. The sensor 32 can include a flowsensor, a gas flow sensor, a fluid flow sensor, a light flow sensor, ora plasma flow sensor.

The sensor 32 can include a pressure sensor, a gas pressure sensor, afluid pressure sensor, a light sensor, an infrared light sensor, anultraviolet light sensor, an x-ray sensor, a cosmic ray sensor, avisible light sensor, a gamma ray sensor, a stress sensor, a strainsensor, a depth sensor, or an electrical characteristic sensor.

The sensor 32 includes a voltage sensor, a current sensor, a viscositysensor, an acoustical sensor, a sound sensor, a listening sensor, athickness sensor, a density sensor, a surface quality sensor, a volumesensor, a physical sensor, a mass sensor, a weight sensor, aconductivity sensor, a distance sensor, an orientation sensor, or avibration sensor.

The sensor 32 can include a radioactivity sensor, a field strengthsensor, an electric field sensor or a magnetic field sensor, a smokedetector, a carbon monoxide detector, a radon detector, an air qualitysensor, a humidity sensor, a glass breakage sensor, or a break beamdetector. The sensor can include a thermal energy sensor, anelectromagnetic sensor, a mechanical sensor, an optical sensor, aradiation sensor, a sensor in contact with a vehicle, or a sensor 32 incontact with a water craft.

The present invention pertains to an apparatus 10 for an application.The apparatus 10 comprises a core device 22 having an integrated circuit36 for the application. The apparatus 10 comprises means for receivingenergy wirelessly and providing power from the energy to the core device22 to power the integrated circuit 36 of the core device 22. Thereceiving means is connected to the core device 22. Preferably, the coredevice 22 includes means for sensing.

The present invention pertains to a method for an application. Themethod comprises the steps of converting RF energy into usable energy.There is the step of preferably powering an integrated circuit 36 of thecore device 22 with the usable energy.

Preferably, there is the step of regulating the usable energy providedto the core device 22. There is preferably the step of storing theusable energy. Preferably, there is the step of providing power to thecore device 22 from an alternative power source 24 in conjunction withthe usable energy.

Alternatively, the core device 22 can include a computer peripheral 34,as shown in FIG. 90. The computer peripheral 34 can include a handheldgame, a gaming system, a game controller, a controller, a keyboard, amouse, a computer terminal, computer storage, or computer equipment.

The present invention can be implemented in numerous ways. A number ofthese ways are depicted in FIGS. 1-90. These figures contain multipleblocks that are configured in multiple ways.

In the figures, an arrow represents the flow of power unless otherwisestated. Single-headed (one-way) arrows represent that the power isflowing from one block to another. The single-headed arrow may representmultiple wires that provide power from one block to multiple parts inthe other block. Two-headed (two-way) arrows represent a single wirethat can have power flow in either direction or multiple wires eachhaving power flow in a single direction.

As an example, a two-headed arrow between an RF power harvesting 20block and a power regulation 26 and/or power storage circuit 28 blockcan represent a single wire that allows harvested power to flow into astorage device such as a capacitor. The same block diagram can alsorepresent two wires between the two blocks with the first wire allowingharvested power to flow into a voltage regulator 26. The second wire canallow the regulated voltage to feedback to the RF power harvesting 20block to provide power to internal components such as transistors toincrease the performance of the RF power harvesting 20 block.

Each block is described in detail below. Each block represents thefunctionality described below associated with it. For instance, the RFpower harvesting 20 block describes a power harvester 20, and the powerregulation 26 and/or power storage circuit 28 block describes a powerregulator 26 and a power storage circuit 28.

Device's Power System Block

The device's power system block includes all components/circuitryrequired to power the device. This block may include an RF powerharvesting 20 block, a power regulation 26 and/or power storage circuit28 block, a power storage block, and/or a power storage charger 30 block(all discussed below).

RF Power Harvesting 20 Block

The RF power harvesting 20 block is connected to an antenna. The antennamay or may not be used as the communications antenna for the core device22 components. The RF power harvesting 20 block is used to convert theenergy captured by the antenna into usable power, such as direct current(DC) voltage.

This block may include antenna matching, rectifying circuitry, voltagetransforming circuitry, and/or other performance optimizing circuitry.The rectifying circuitry may include a diode(s), a transistor(s), orsome other rectifying device or combination. Examples of the rectifyingcircuitry include, but are not limited to, half-wave, full-wave, andvoltage doubling circuits.

The output of the RF power harvesting 20 block is a DC voltage orcurrent. The RF power harvesting 20 block may accept feedback (or input)from other circuitry or blocks, which may be used to control theharvesting circuitry to improve the performance or vary the output. Thisfeedback may include, but is not limited to, a DC voltage or a clockfrom the core device 22 components.

U.S. Pat. No. 6,615,074 (FIGS. 8, 9, 12 a, 12 b, 13, 14), incorporatedby reference, herein, shows numerous examples of RF power harvestingcircuits that can be used to implement the block and function described.

Power Regulation 26 and/or Power Storage Circuit 28 Block

It may be necessary to regulate the converted power (i.e., hold thepower at a constant level) for specific devices. The devices that wouldneed this block require a fairly constant voltage or current. Deviationsfrom the required values may cause the device to not perform within itsspecifications.

The regulation can be implemented in many different ways. The block canbe as simple as using a Zener diode, or as complicated as using anintegrated circuit such as a linear voltage regulator 26 or switchingregulator 26 to hold the voltage at a constant level.

Certain devices have a more tolerable power requirement. For thesedevices, the regulation stage may be excluded.

This block may also include, with or without the regulation, a storagedevice such as a capacitor, a battery, or some other device able tostore charge. The output from the power regulation 26 and/or powerstorage circuit 28 block may be used as feedback to other blocks withinthe device's power system block or to the alternative power sources 24block (described below), if they require a regulated supply voltage orstored power.

U.S. Pat. No. 6,894,467 (FIGS. 1, 3), Linear Voltage Regulator,incorporated by reference, herein, is an example of a practicalapplication of implementing the regulation described in the block. U.S.Pat. No. 6,297,618 (FIGS. 1-4), Power storage device and method ofmeasuring voltage of storage battery, incorporated by reference, herein,is an example of a practical application of implementing the storagedescribed in the block.

Power Storage Charger 30 Block

The power storage charger 30 block may be needed if a power storagecomponent of the device requires a special charging mechanism, such aspulse charging or trickle charging. This block controls how the capturedand converted power is supplied to the power storage component.

U.S. Pat. No. 6,836,095 (FIGS. 1-3), Battery Charging Method andApparatus, incorporated by reference herein, is an example of apractical application of implementing the special charging mechanismdescribed in the block.

Power Storage Block

If a device has intermittent power requirements, it may be necessary tostore the captured power for use at a later time. The power can bestored in the power storage block, which could include a battery, acapacitor, and/or another type of power storage component. Power storagecomponents include, but are not limited to, batteries (rechargeable andnon-rechargeable), capacitors, inductors, fuel cells, and other powerstorage elements.

The output from the power storage block may be used as feedback to otherblocks within the device's power system or to the alternative powersources 24 block, if they require a dedicated and predictable supplyvoltage.

U.S. Pat. No. 6,297,618 (FIGS. 1-4), Power Storage Device and Method ofMeasuring Voltage of Storage Battery, incorporated by reference herein,is an example of a practical application of implementing the storagedescribed in the block. U.S. Pat. No. 6,835,501, Alkaline RechargeableBattery, incorporated by reference herein, is also an example of apractical application of implementing the storage described in theblock.

Core Device 22 Components Block

The core device 22 components block is the portion of the device that isreceiving power from the device's power system. This block may be, butis not limited to, the devices listed in the subsequent pages of thisdocument. It may be advantageous for the core device 22 components blockto communicate with any of the blocks that are supplying power to it.This communication can include, but is not limited to, a feedbackcontrol signal such as a clock or an ON/OFF command. As an example, thedevice may want to turn off the alternative power sources 24 block if itis receiving sufficient power from the RF power harvesting 20 block.

Alternative Power Sources 24 Block

RF energy harvesting also has the ability to be augmented by other typesof power harvesting, storage components, or dedicated sources (e.g.power line). The alternative power sources 24 block shows how this typeof system could be implemented. The augmenting power harvestingtechnologies include, but are not limited to, solar, light (visible andnon-visible), piezoelectric, vibration, acoustic, thermal,microgenerators, wind, and other environmental elements. This block canwork independently or have communication with other blocks.

U.S. Pat. No. 6,784,358, Solar Cell Structure Utilizing an AmorphousSilicon Discrete By-Pass Diode, incorporated by reference herein, is anexample of a practical application of implementing an alternative powersource 24 described by the block. U.S. Pat. No. 6,858,970,Multi-Frequency Piezoelectric Energy Harvester, incorporated byreference herein, is also an example of a practical application ofimplementing an alternative power source 24 described by the block.

Power Regulation 26, Storage 28 and/or Storage Charging 30 Block

The power regulation 26, storage 28 and/or storage charging 30 blockcontains all the combinations of the power regulation 26 and/or powerstorage circuit 28 block, power storage charger 30 block, and powerstorage block. This block is used in the later figures to reduce thenumber of figures needed to show how the blocks can interconnect.

The disclosed invention is an apparatus and method for an applicationfor retrieving radio frequency (RF) energy by an antenna, convertingthat energy into direct current (DC) power, regulating that energy usingan optimized circuit, storing that energy in an optimized component,and/or supplying the power for a specific device.

Retrieval of RF Energy

The RF energy is retrieved from the environment by the use of theantenna. The antenna can be shared or standalone with respect to anantenna used for the device's wireless communication. FIGS. 54-56 show adevice that has an antenna A for use by the RF power harvester 20 and anantenna B used for wireless one-way or two-way communication. FIGS.57-59 show a device where the antenna is shared by both a device'scommunication module (within the core device 22 components) and the RFpower harvester 20. In terms of form factor, the antenna used by theapparatus 10 can be a separate component or integrated directly into theform factor of the device.

The antenna is able to capture two types of available RF energy. Thefirst type of energy exists as ambient RF energy. This type of RFsurrounds us in our day-to-day lives and is usually generated to carryone way or two-way combinations of voice, video and data communications.The sources that the antenna can harvest from include, but are notlimited to, medium-frequency AM radio broadcast, very-high-frequency(VHF) FM radio broadcast and television broadcast, ultra-high-frequency(UHF) broadcast, cellular base stations, wireless data access points,super-high-frequency (SHF) frequencies, and the industrial, scientific,and medical (ISM) bands. These sources cover transmission frequenciesfrom 300 kHz to 30 GHz.

The second type of energy available is directed RF energy. This type ofRF energy is directed from a transmitter specifically designed todeliver RF energy for harvesting by the antenna. The transmitter can beconfigured as a standalone device or integrated into an existing device.

Conversion of the Energy into DC

The RF energy captured by the antenna must be converted into a usefulform of energy for the specific device. This conversion is shown inblock form in all FIGS. (1-90) as the RF power harvesting 20 block. Themost common form of useable energy is DC energy. To perform thisconversion, the block includes circuitry to rectify the capturedalternating current (AC) energy to create DC energy. The rectificationin this block can be done with a diode(s), a transistor(s), or someother rectifying device or combination.

Regulation of the Energy

It may be necessary to regulate the converted power (hold the power at aconstant level) for specific devices. FIGS. 2-7, 10-17, and 22-53 showhow this regulation can be implemented using a power regulation 26and/or power storage circuit 28 block. The devices that would need thisblock require a fairly constant voltage or current. Deviations from therequired values may cause the device to not perform within itsspecifications. The regulation can be implemented in many differentways. The block can be as simple as using a Zener diode, or ascomplicated as using an integrated circuit such as a linear voltageregulator 26 or a switching regulator 26 to hold the voltage at aconstant level. Certain devices have a more tolerable power requirement.For these devices, the regulation stage may be excluded.

Storage of the Energy

If a device has intermittent power requirements, such as the devicesexampled by FIGS. 2-53, it may be necessary to store the captured powerfor use at a later time. The power can be stored in the power storageblock or the power regulation 26 and/or power storage circuit 28 block.Storage devices can include, but are not limited to, a battery, acapacitor, or another type of power storage component. In certainapplications, it may be necessary to include additional circuitry thatcontrols how the power is transferred to the storage device. The powerstorage charger 30 block is shown in FIGS. 18-53. This may be needed ifthe power storage component requires a special charging mechanism suchas pulse charging or trickle charging. Power storage components include,but are not limited to, batteries (rechargeable and non-rechargeable),capacitors, inductors, fuel cells, and other storage elements. There aredevices that will not require storage. These devices can run directlyoff of the converted power. These devices also may or may not requireregulation of the captured power.

Supplying the Power

The captured DC power, which may or may not be regulated and/or stored,is supplied to the device, which is represented by the core device 22components block in the figures. This may be a single connection or itmay supply multiple parts of the device with power.

RF energy harvesting also has the ability to be augmented by other typesof power harvesting or storage components. Other power harvestingtechnologies include, but are not limited to, solar, light (visible andnon-visible), piezoelectric, vibration, acoustic, thermal,microgenerators, wind, and other environmental elements. Power storagecomponents include, but are not limited to, batteries (rechargeable andnon-rechargeable), capacitors, inductors, fuel cells, and other storageelements. FIGS. 60-88 show how the alternative power sources 24 blockcan be connected to an RF energy harvesting system. These figure showhow the RF energy harvesting 20 block and the alternative power sources24 block can work independently or have communication with each other.The antenna configurations shown in FIGS. 54-59 are still applicablewith the addition of an alternative power sources 24 block. Theseantenna configurations can be applied to FIGS. 60-88.

RF energy harvesting also has the ability to provide a backup to deviceson-grid (tethered) or with reliable power sources, which can be used incase the primary power source is lost. As an example, it may be mandatedby regulations that a sensor has auxiliary power in case the primarysupply is lost. It could be possible to use a rechargeable battery thatobtains its charge from the primary supply when in operation. However,if the primary supply is lost for a time greater than the life of therechargeable battery, the specification of uninterrupted power is notmet. RF energy could be used to supply power to the described devicewhile the primary supply is not available. The primary supply couldinclude, but is not limited to, an on-grid connection, a generator, abattery, or other reliable power supply.

RF energy harvesting with or without alternative source augmentation isapplicable to provide electric power directly or indirectly to a rangeof electronic components contained in any specific electrical orelectronic device and includes, but is not limited to:

-   -   Passive electronic components, active electronic components;    -   Resistors, fixed resistors, variable resistors, thermistors,        thyristor, thermocouple;    -   Capacitors, Electrolytic Capacitors, Tantalum Capacitors,        Ceramic Capacitors, Multilayer Ceramic Capacitors, Polystyrene        Film Capacitors, Electric Double Layer Capacitors (Super        Capacitors), Polyester Film Capacitors, Polypropylene        Capacitors, Mica Capacitors, Metallized Polyester Film        Capacitors, Variable Capacitors;    -   Diodes, Voltage regulation diodes, light-emitting diodes,        organic light-emitting diodes, Variable capacitance diodes,        Rectification diodes, Switching diodes, Regulation Diodes, Diode        bridges, Schottky barrier diodes, tunnel diodes, PIN diodes,        Zener diodes, Avalanche diodes, TVSs;    -   Integrated circuits, microcontroller unit (MCU), microprocessor        unit (MPU), logic circuits, memory, printed circuits, circuit        boards, printed wiring boards;    -   Transistors, MOSFETs, FETs, BJTs, JFETs, IGBTs, Relays,        Antennas, semiconductors, conductors, inductors, relays, diacs,        triacs, SCRs, MOVs;    -   Fuses, circuit breakers;    -   Batteries, Non-rechargeable batteries, rechargeable batteries,        coin cell batteries, button cell batteries, alkaline batteries,        lithium batteries, lithium ion batteries, lithium polymer        batteries, NIMH batteries, NICAD batteries, Lead acid batteries,        Zinc air batteries, Manganese Lithium batteries, Niobium        Titanium Lithium batteries, Vanadium Pentoxide Lithium        batteries, Carbon Zinc batteries, Zinc Chloride batteries,        Lithium Thionyl Chloride batteries, Manganese Dioxide batteries,        Lithium Poly-Carbonmonofluoride batteries, Lithium Manganese        Dioxide batteries, Lithium Chloride batteries, Lead Acid Calcium        batteries, Lead Acid Tin batteries, Oxy Nickel batteries, Silver        Oxide batteries, Magnesium batteries;    -   Inductors, Coils, High Frequency Coils, Toroidal Coils,        Transformers, switches, chokes;    -   Motors, DC motors, stepper motor, AC motors, Fans;    -   Crystals, Oscillators, Clocks, Timers; and    -   Displays, LCDs, LED displays.

RF energy harvesting with or without alternative source augmentation isapplicable across a range of markets and specific devices and includesbut is not limited to:

Consumer electronics:

-   -   Electronic equipment, wired devices, battery powered devices,        wireless communication devices, cell phones, telephones, phones,        cordless phones, portable phones, Bluetooth devices, Bluetooth        headsets, hands-free headsets, headsets, headphones, Wireless        headsets, radios, AM/FM radios, shortwave radios, weather        radios, Two-way radios, portable radio, lights, lanterns,        portable lights, flashlights, nightlights, spotlights, search        lights, calculators, graphing calculators, desk calculators,        clocks, alarm clocks, wall clocks, desk clocks, travel clocks,        watches, wristwatches, pocket watches, stop watches, timers,        voice recorders, Dictaphones, laser pointers, power tools,        cordless power tools, electronic razors, electric razors,        handheld games, gaming systems, game controllers, wireless game        controllers, remote controls, battery chargers, computers,        portable computers, keyless entry, toys, toy guns, toy laser        guns, games, microphones, musical instruments, musical effects        processors, musical instrument tuners, metronomes, electronic        chord charts, door openers, garage door openers, PDA, Cameras,        Video recorders, Multi-meter, electronic test equipment,        hand-held electronics, portable electronics, wireless pens,        sound generators, noise generators, language translators,        electric toothbrushes, portable televisions, pagers,        transceivers, toy vehicles, remote control vehicles, toy planes,        remote control planes, pet containment systems, invisible fence        pet sensors, memory backup, base station battery backups,        appliance battery backups, uninterrupted power supplies, GPS        devices, memory retention power supplies, metal detectors, stud        finders, metal stud finders, stun guns, tazers, wearable        devices, baby monitors, intercoms, doorbells, wireless        doorbells, electronic office supplies, electronic staplers,        radar jammers, radar detectors, digital scales, microfilm        cassettes, video head testers, compasses, noise canceling        headphones, air samplers, depth finders, barometers, weather        measurement instruments, data transfer devices, automatic        distress signaling unit, Wireless audio speakers, Satellite        radios, Police scanners, Car navigation systems (GPS devices),        Decorative lights, Christmas lights, garden lights, lawn lights,        ornamental lights, porch lights;    -   Multi-media players: MP3, DVD, analog music players, CD players,        tape players, digital music players, digital video players,        minidisc; and    -   Computer: keyboards, mice, peripherals, computer equipment,        electronic computers, computer storage, computer terminals;

Building/Industrial Automation:

-   -   Sensors: Position, elevator, temperature, fire, accelerometers,        level, gas level, fluid level, light level, flow, gas flow,        fluid flow, light flow, plasma flow, pressure, gas pressure,        fluid pressure, motion, light, infrared light, ultraviolet        light, X-rays, cosmic rays, visible light, gamma rays, chemical,        stress, strain, depth, electrical characteristics, voltage,        current, viscosity, acoustical, sound, listening, thickness,        density, surface quality, volume, physical, mass, weight, force,        conductivity, distance, orientation, vibration, radioactivity,        field strength, electric field strength, magnetic field        strength, occupancy, smoke detector, carbon monoxide detector,        radon detector, air quality, humidity, glass breakage, break        beam detector;    -   Controls: Position, elevator, temperature, fire, accelerometers,        level, gas level, fluid level, light level, flow, gas flow,        fluid flow, light flow, plasma flow, pressure, gas pressure,        fluid pressure, motion, light, infrared light, ultraviolet        light, X-rays, cosmic rays, visible light, gamma rays, chemical,        stress, strain, depth, electrical characteristics, voltage,        current, viscosity, acoustical, sound, listening, thickness,        density, surface quality, volume, physical, mass, weight, force,        conductivity, distance, orientation, vibration, radioactivity,        field strength, electric field strength, magnetic field        strength, occupancy, smoke detector, carbon monoxide detector,        radon detector, air quality, humidity; and    -   Devices: Thermostats, light switches, door locks, smart-card        door locks, lighting, emergency lighting, motion lighting,        safety lighting, highway lighting, construction lighting, sign        lighting, roadway sign lighting, construction sign lighting,        automatic flushing units, automatic soap dispenser, automatic        paper towel dispenser, automatic faucets, automatic door        sensors, identification reader, fingerprint reader, credit card        readers, card readers, valve actuators, gauges, analog gauges,        digital gauges, fire extinguishers, wireless switches, remotely        operated inspection equipment, gas/oil pipeline monitoring        systems, robotic pipeline inspection gauges, “auto-reclosers”        for electric power lines, sonar buoys, telemetry systems,        electronic record tracking systems, robbery tracking devices,        interrogators, programmers, emergency exit alarms, alarms, flood        alarms, gas alarms, electronic entry systems, security keypads,        silo transducers, data recorders, signal tracers, anti-static        strap testers, radiosonde weather balloons, utilities load        controllers, profilometers, noise cancellation equipment,        infrared beacons;

Military/Government:

-   -   Tracking tags: Weapons, vehicle, soldier, gear/assets, staff,        general population, security access badges;    -   Sensors: Proximity, intrusion, environmental,        chemical/biological; and    -   Equipment: Battery charger, surveillance, card readers,        identification reader, fingerprint reader, retinal scanners,        satellites, rockets, space vehicles, search and rescue        transponders (SARTs), emergency position-indicating rescue        beacons (EPIRBs), emergency locator transmitters (ELTs),        military radios, electronic toll collection systems, postal        tracking systems, communications, thermal imaging, night vision,        training targets, field medical equipment, house arrest        monitors, laser tags, electronic parking meters, multiple        integrated laser engagement system, munitions and mines, ship        sensors;

Utility:

-   -   Gas consumption meters, water consumption meters, and electric        consumption meters;

Logistics & Supply Chain Management:

-   -   Radio-frequency identification devices (RFID), RFID readers;    -   Tracking: Asset tags, cargo container location beacons,        transponders, transceivers; and    -   Devices: Smart price tags, smart shelving, handheld barcode        scanner, barcode scanners, credit card readers, card readers,        retail signage, hotel door locks;

Homeland Security:

-   -   Sensors: Occupancy, proximity, environmental,        chemical/biological, motion, position; and    -   Metal detector wand;

Medical:

-   -   Implantable: cochlear implants, neural stimulators, pace makers,        medication administration, defibrillator;    -   Body function monitors: pressure, temperature, respiration,        blood oxygenation, insulin, hearing aid, pulse, EKG, heart,        Holter;    -   Tracking tags: Patient, baby identification, assets, supplies,        staff, medication, instruments;    -   Devices: Home healthcare equipment, ambulatory infusion pumps,        blood analyzers, biofeedback systems, bone growth stimulators,        thermometers, digital thermometers, stimulators, galvanic        stimulators, muscle stimulators, pediatric scales; and

Agriculture—livestock tracking and asset tracking:

-   -   Tracking: livestock, asset, wildlife tracking devices; and    -   Equipment: cattle prods;

Automotive:

-   -   Automotive antennas, Automotive Audio Systems, Automotive        Lighting, Automotive Video Systems, Computers, Processors,        Controls, Switches, Electric Motors, Actuators, Ignition        Systems, Starter Systems, Injection Systems, Powertrain        Electronics, Radar Detectors, Proximity Detectors, Safety        Systems, Security Systems, Sensors, Regulators, Distributors,        Vehicle Control, Wiper Systems, Washer Systems, Radio, Video        Systems, Entertainment Systems, Navigation Systems, GPS systems,        Power Mirror Systems, Emission control systems;

Appliances:

-   -   Monitoring systems and control systems for major and small        appliances including washing machines, dryers, refrigerators,        freezers, coolers, air conditioners, humidifiers, dehumidifiers,        air purifiers, air filters, fans, furnaces, water heaters,        boilers, space heaters, sowing machines, ice makers, microwave        ovens, convection ovens, ovens, toaster ovens, ranges, range        hoods, cooktops, stoves, stovetops, crock pots, hot plates,        dishwashers, garbage disposals, can openers, vacuum cleaners,        blenders, mixers, food processors, irons, coffee makers,        toasters, grills, hair dryers, electric tooth brushes, electric        razors, electric drills, electric screwdrivers, chainsaws,        lawnmowers, push mowers, riding mowers, trimmers, brush cutters,        pruners, edgers, vending machines;

Ventilation, Heating, Air-Conditioning, and Commercial RefrigerationEquipment:

-   -   Monitoring systems, control systems;

Engine, Turbine, and Power Transmission Equipment;

Monitoring systems, control systems;

Other General Purpose Machinery Manufacturing:

-   -   Monitoring systems, control systems;

Telecommunications:

-   -   Monitoring systems, control systems;    -   Portable;

Aircraft:

-   -   Monitoring systems, control systems, actuator systems, sensors.

It should be noted that devices within a specific category may beapplicable across multiple areas even if they are not specificallylisted. (e.g., temperature sensors apply to Industrial and BuildingAutomation and Appliances).

To retrofit or redesign the devices listed, it is possible to implementthe described systems in numerous ways. It may be advantageous to leavethe device design as-is including the existing power supply. As anexample, a device may use non-rechargeable batteries to operate. Thedevice will most likely have a protection circuit to prevent damage ifthe batteries are installed incorrectly. The protection mechanism iscommonly a diode inline with the positive terminal of the battery. Inthis case, the RF power harvester 20 with or without the alternativepower source 24 could be inserted, with an antenna, into the device. Thepower generated by the RF power harvester 20 (and the alternative powersource 24, if applicable) could be connected to the device after theprotection mechanism described to avoid potential charging of anon-rechargeable battery.

Another way to configure the device's power system is to replace thenon-rechargeable batteries with rechargeable batteries. In thisinstance, the output from the RF power harvester 20 (and alternativepower source 24) could be connected to either side of the protectionsdevice. If the connection is before the protection mechanism, the RFpower harvester 20 (and the alternative power source 24, if applicable)will recharge the battery and supply power to the device. If theconnection is after the protection mechanism, the RF power harvester 20(and the alternative power source 24, if applicable) will supply powerto the device and the battery will supply any extra power needed thatcould not be supplied by the RF power harvester 20 (and the alternativepower source 24, if applicable). It should be noted that the protectiondevice in this case is not needed for proper operation. Its onlyfunction would be to protect the batteries from being installedincorrectly. An antenna could be contained inside or placed on theoutside of the device.

Another configuration of the device's power system is to remove theexisting batteries and install the RF power harvester 20 (and thealternative power source 24) in the enclosure provided for thebatteries. An antenna could be contained inside or placed on the outsideof the device.

Yet another method of configuring the device's power system would be toreduce the number of batteries and replace them with the RF powerharvester 20 (and the alternative power source 24). In this case, theoutput from the system would be connected to the batteries in series orparallel depending on the original battery configuration. An antennacould be contained inside or placed on the outside of the device.

An additional option, would be to completely redesign the product andintegrate the required circuitry and storage components into the device.This method is probably the most advantageous because it can fully takeadvantage of the benefits offered by the RF power harvester 20 (and thealternative power source 24). An antenna could be contained inside orplaced on the outside of the device.

If the RF power harvester 20 (and the alternative power source 24) isused as a backup to the primary power supply, a switch could beimplemented into the system in order to switch the RF power harvester 20(and the alternative power source 24) on when the primary source islost. In this case, an antenna could be contained inside or placed onthe outside of the device.

To show the flexibility of RF energy harvesting, several products wereretrofitted to include an RF power harvester 20 (energy harvestingcircuitry). These products include a wireless keyboard, a wall clock,and a desk calculator.

The wireless keyboard is an example of recharging and augmenting abattery to supply power to a device. This system is shown in FIG. 13.The output from the regulation circuitry recharges the battery andsupplies power to the keyboard. The battery is also used to supply powerto the keyboard. The keyboard also includes a separate antenna forreceiving power and for data communications. The antenna configurationcan be seen in FIG. 55.

The wall clock is an example of a direct powering system. The wall clockwas retrofitted to include an RF power harvester 20 and the internal AAbattery was removed. This system is shown in FIG. 2. The wall clock didnot need regulation, but did require a capacitor for storage to supplythe pulse of power to move the second hand.

The calculator is an example of using RF energy harvesting with anotherenergy harvesting technology. The calculator had an internal 1.5V coincell battery and a small solar panel. The internal battery was removed,however, the solar panel was left intact. This system is shown in FIG.60. In this system, the calculator can receive power from both the solarpanel and the RF power harvester 20 to eliminate the need for a battery.

As an additional example, an RF power harvester 20 (energy harvestingcircuit) similar to the ones shown in U.S. Pat. No. 6,615,074 (FIGS. 8,9, 12 a, 12 b, 13, 14), was connected in series with a 0.5V solar cell.Individually, the solar cell was able to provide 0.480V to a 10 kilo-ohmresistor, which was being used to simulate the core device 22components. This corresponds to 23 microwatts. The RF power harvestingcircuit by itself was able to provide 2.093V across the 10 kilo-ohmresistor when being supplied by 1 milliwatt of RF power. Thiscorresponds to 438 microwatts. The two circuit outputs were thencombined in series by connecting the output from the RF energyharvesting circuit to the ground of the solar cell. The output of thesolar cell was then connected to the resistor. The other end of theresistor was connected to the ground of the RF energy harvestingcircuit. The voltage across the resistor with the circuits connected asshown in FIG. 63 was 2.445V. This corresponds to 598 microwatts.

As can be seen, the combination of the two technologies produces aresult higher than the addition of the individual powers. From this, itcan be determined that the two technologies can cooperate in a way thatproduces favorable results.

In the example given, the solar cell produces current to supply the loadand helps to bias the RF rectifying diodes, which allows the RF energyharvesting circuit to operate a higher efficiency. The solar cell alsochanges the impedance seen by the RF energy harvesting circuit, whichproduces a beneficial result. To be more specific, when examining thepower output of the individual circuit (solar and RF power harvesting),the sum of the power captured by the individual circuits was 23 μW+438μW=461 μW. However, when the two circuits are combined and are allowedto work in conjunction with one another, the output power becomes 598μW. This result shows that combining the two power-harvestingtechnologies produces a 30 percent increase in the output power for thisexample. This same technique can be applied to multiple energyharvesting technologies to produce even greater output power. Theequations for this example are shown below.

Individual CircuitsP _(I) =P ₁ +P ₂ + . . . +P _(N)

Combined CircuitsP _(C) >P _(I) =P ₁ +P ₂ + . . . +P _(N)

-   -   where P_(I) is the sum of the individual output powers        -   P_(C) is the output of the combined circuit        -   P₁ is the output power from the first power harvesting            technology        -   P₂ is the output power from the second power harvesting            technology        -   P_(N) is the output power from the N^(th) power harvesting            technology        -   N is the number of power harvesting technologies or            circuits.

As can be seen by the previous examples, RF energy harvesting can beused alone or in conjunction with alternative power sources to power awide range of devices. The addition of RF energy harvesting technologyto the device allows for increased battery life, increasedfunctionality, or the removal of the primary battery.

Although the invention has been described in detail in the foregoingembodiments for the purpose of illustration, it is to be understood thatsuch detail is solely for that purpose and that variations can be madetherein by those skilled in the art without departing from the spiritand scope of the invention except as it may be described by thefollowing claims.

What is claimed is:
 1. An apparatus, comprising: a first antennaconfigured to wirelessly receive energy from a source that is remotefrom the apparatus and in a far-field region of the first antenna and asecond antenna; the second antenna different from and electricallyisolated from the first antenna, the second antenna configured towirelessly communicate with the source; a power harvester electricallycoupled to the first antenna and configured to convert the energyreceived at the first antenna to a DC voltage; a radio-frequencyidentification (RFID) device electrically coupled to the power harvesterand to the second antenna, the RFID device configured to wirelesslycommunicate with the source via the second antenna; an integratedcircuit configured to operate based on the DC voltage; and a sensorelectrically coupled to the integrated circuit, the sensor configured tooperate based on the DC voltage and to detect at least one of anenvironmental condition associated with a location of the apparatus or aphysical condition associated with an item coupled to the apparatus. 2.The apparatus of claim 1, further comprising: a regulator coupled to thepower harvester and configured to regulate the DC voltage to produce aregulated DC voltage, the sensor configured to operate based on theregulated DC voltage received from the regulator.
 3. The apparatus ofclaim 1, wherein the integrated circuit is configured to perform anapplication associated with the at least one of the environmentalcondition or the physical condition detected by the sensor.
 4. Theapparatus of claim 1, further comprising: an electronic displayconfigured to operate based on the DC voltage.
 5. The apparatus of claim1, wherein the sensor includes at least one of a temperature sensor, amotion sensor, a vibration sensor, a humidity sensor, an orientationsensor, or a position sensor.
 6. The apparatus of claim 1, wherein theRFID device does not operate based on a battery, and the sensor does notoperate based on a battery.
 7. The apparatus of claim 1, wherein theapparatus is a RFID tag.
 8. An apparatus, comprising: an antennaconfigured to wirelessly receive energy from a source that is remotefrom the apparatus and in a far-field region of the antenna; a powerharvester electrically coupled to the antenna and configured to convertthe energy received at the antenna to a DC voltage; a radio-frequencyidentification (RFID) device electrically coupled to the antenna andconfigured to wirelessly communicate with the source via the antenna,the RFID device operatively coupled to the power harvester and includingan integrated circuit configured to operate based on the DC voltage; anda sensor electrically coupled to the RFID device and the powerharvester, the sensor configured to operate based on the DC voltage andto detect at least one of an environmental condition associated with alocation of the apparatus or a physical condition associated with anitem coupled to the apparatus, the integrated circuit configured toperform an application associated with the at least one of theenvironmental condition or the physical condition detected by thesensor.
 9. The apparatus of claim 8, wherein the power harvester isconfigured to wirelessly communicate with the source via the antenna.10. The apparatus of claim 8, wherein the sensor is electrically coupledto the antenna and is configured to wirelessly communicate with thesource via the antenna.
 11. The apparatus of claim 8, furthercomprising: a regulator coupled to the power harvester and configured toregulate the DC voltage to produce a regulated DC voltage, theintegrated circuit configured to operate based on the regulated DCvoltage received from the regulator.
 12. The apparatus of claim 8,further comprising: an electronic display configured to operate based onthe DC voltage.
 13. The apparatus of claim 8, wherein the sensorincludes at least one of a temperature sensor, a motion sensor, avibration sensor, a humidity sensor, or a position sensor.
 14. Theapparatus of claim 8, wherein the RFID device does not operate based ona battery, and the sensor does not operate based on a battery.
 15. Anapparatus, comprising: an antenna configured to wirelessly receiveenergy from a source that is remote from the apparatus and in afar-field region of the antenna; a power harvester electrically coupledto the antenna and configured to convert the energy received at theantenna to a DC voltage to produce a power associated with the DCvoltage; a regulator coupled to the power harvester and configured toregulate the power associated with the DC voltage to produce a regulatedpower; a radio-frequency identification (RFID) device electricallycoupled to the antenna and configured to wirelessly communicate with thesource via the antenna, the RFID device electrically coupled to thepower harvester and the regulator, the RFID device including anintegrated circuit configured to operate based on at least one of thepower received from the power harvester or the regulated power receivedfrom the regulator; and an electronic display electrically coupled tothe RFID device and configured to operate, at least in part, based onthe regulated power received from the regulator.
 16. The apparatus ofclaim 15, wherein the electronic display is electrically coupled to theregulator, the electronic display is configured to operate based on theregulated power received from the regulator and the power received fromthe power harvester.
 17. The apparatus of claim 15, wherein theelectronic display is one of a liquid-crystal display (LCD) or alight-emitting diode (LED) display.
 18. The apparatus of claim 15,further comprising: a sensor configured to operate, at least in part,based on the regulated power received from the regulator, the sensorincluding at least one of a temperature sensor, a motion sensor, avibration sensor, a humidity sensor, or a position sensor.
 19. Theapparatus of claim 15, wherein the power harvester is configured towirelessly communicate with the source via the antenna.
 20. Theapparatus of claim 15, wherein the RFID device does not operate based ona battery, and the electronic display does not operate based on abattery.